Shek, I think your Monster should be just fine, the SP I'm referring to at Newegg has cable, phone and ethernet protection, that's why I like it. The other SP is a meter pan suppressor, it is connected outside my home inside the electric utility meter where my service comes into the house, it has green and red lights, green means it is protected and not tripped, red designates a severe power surge and needs to be reset by the utility company, like Steve said it can sustain some severe surges and keep on ticking.
The reason for the inside devices is mainly for other lines coming in that are not a part of the meter pan, like cable and phone. It helps me to rest easier. I really don't know anything about your Monster, but if it is older you may want to consider one that offers cable, phone etc. protection.